The owners corporation of the 120-unit apartment block, Kingston Place stage two on Eyre Street, took legal action against the firm in September last year, after first complaining to the ACT's building regulator in August 2016.

It is understood the alleged defects range from structural cracking of the major concrete slab in the underground car park and water retention tank in the building's basement to poor workmanship on many of the development's balconies.

But the firm is vigorously defending itself against the allegations in court, claiming the defects were not its fault, but may have been caused variously because of poor workmanship by the engineers, AWT [now owned by WSP], or the tiling firm on the balconies, Saba Bros.

The ACT government is also a party to the case due to the owners corporation arguing the government should not have issued a certificate of occupancy and use for the development, and all defendants have not admitted any liability for the alleged problems.

The company is also currently selling thousands of new units across the city, including at One City Hill, Park Avenue and Highgate in Civic, Parc in Macquarie, Nova in Dickson and Jacqueline's Rise in Watson.

It is also selling units in developments in Queensland, including Sandbar at Burleigh Heads, Otto at Mermaid's Beach and Koko, Opus and Qube at Broadbeach, as well as the Miramar tower in Geelong, Victoria.

On its website, the company says it will deliver certainty, quality, transparency and "simplexity" for all buyers of its units, and its team was dedicated "to providing versatile and liveable apartments of exceptional quality".

While The Canberra Times has not seen a formal estimate of the cost of potential rectification works, it would likely run into millions of dollars, given allegations almost all of the 122 balconies need repairs, as well as the basement car park concrete slab and water retention tank.

Despite the Kingston owners corporation formally complaining to the ACT's building compliance regulator Access Canberra in August 2016, the regulator has taken little action to force the developer to actually rectify the alleged problems.

It remains unclear what action the regulator has taken regarding the owners corporation's complaint made in August 2016, with none of the parties commenting on the matter.

The complaint, detailed in the owners corporation's statement of claim and an affidavit from the ACT Government Solicitor, claims that despite the alleged defects being reported to the developer, Morris Property Group, for the most part the company had "denied responsibility for the defects and refused to remedy" them.

In the complaint, Access Canberra staff also wrote the owners corporation was concerned as early as March 2016 that the company was becoming "more confrontational", citing an email from that period that said the company believed it had no obligation to take any action and "further we do not intend to take any action".

"We suggest the owners corporation takes action it deems appropriate at its election and cost, which may include notifying its insurer," the email cited in the complaint reads.

The complaint also referred to the developer's attitude to requests to rectify the alleged defects as having "further hardened" after the owners corporation asked for cracks in the building's water retention tank to be fixed.

While the case has been playing out in the ACT Supreme Court, it is understood the parties to the case will meet in the next fortnight for a mediation in an effort to find a potential agreement on what to do about the matters raised.

Several individuals and their legal representatives declined to comment for this report, including Saba Bros, the owners corporation, and WSP on behalf of AWT Consulting Engineers, now a subsidiary of WSP.

Morris Construction Corporation's legal representative, Ben Aulich, said in a statement the firm was working very closely with the owners corporation in a collaborative manner to resolve purported issues with the building.

"Whilst it is not appropriate to comment on this matter because it is before the court, we hope to have a resolution for all parties in early December through a conciliatory mediation," he said.

A spokeswoman for the territory government said that as the matter was before the Supreme Court, it was not appropriate to comment.

Questions put to the government regarding what action it had taken to help resolve the issues, and how many of the company's development applications the government had approved since the matter came before the courts, among others, remain unanswered.